Improvement in millstone-dresses



2 Sheets-Sheet 2.

E. S. COX. Millstone-Dress.

Patented Oct. 8, 1878. izyf.

W/L/z @8821.50

UNITED STATES PATENT OEEICE.

ELBERT S. COX, OF JONESBOROUGII, TENNESSEE.

IMPROVEMENT IN MlLLSTONE-DRESSES.

Specification forming part of Letters Patent N0. 208,716, dated October H. 1979; application filed September 10, 1879.

To all whom 'it may concern Be it known that I, ELBERT S. Cox, of Jonesborough, Washington county, and State of Tennessee, have invented a new and Improved Dress for the Grinding-Stones of Flouring- Mills; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanyin g drawings, forming a part of this specification, in Which Figure l is a top view of the lower millstone. Fig. 2 is a view of the peripheries of both the upper and lower stones, as when placed together. Fig. 3 is a diagram, giving a longitudinal profile of the upper and lower landsurfaces of the stones. Fig. 4 is a diagram, giving a longitudinal profile of the furrow-surfaces of the stones. Fig. 5 is a vertical crosssection of the stones in the line y y of Fig. l. Fig. 6 is a diagram illustrating the manner in which the' grinding-surfaces of the respective stones cross one another when grinding; and .F ig. 7 is a perspective view of a portion of the lower or bed stone.

The object of my invention is to provide a dress for iouring-millstones by which the grain in the act of being ground will first be divested of its outer cuticle or bran 5 second, be gradually more and more granulated as it passes outwardly from the eye of the stones; and, next, be delivered upon a plane finishingsurface extending inwardly a proper distance from the periphery of the stones, where itis finally reduced to the condition of perfectlyground flour.

My invention also has for its object the ventilation of the crushed grain during the process of grinding with surfaces such as hereinafter described; and as the actual flouring of the grain takes place at or near the periphery of the stones, the injurious over grinding and heating of the our is obviated, which is so great an obj ection under the old mode of dressing millstones. Under the ordinary mode of dressing, the reduction of the grain to the actual condition of flour commences near the eye of the stones, and thence outwardly the flour is, so to speak, ground over and over before it is finally delivered from the stones. Such grinding not only destroys the life of thc flour,

but, it is supposed, generates an explosive dust which is liable to destroy the mill itself.

Again, under my mode of dressing, the surface of the stones, where the louring proper of the grain takes place, is made as smooth as possible by allowing the stones to run in contact while water is passed between over such surface. A flouring-surface proper thus produced I find to be far superior to the usual mode of delicately cracking such surface with a pick, since by my dress grit7 in the our is avoided, which is so common to the old style of dress.

In the accompanying drawings, a indicates the flouringsurface proper of the burr-millstones, the upper stone, A, and the lower or bed stone, B, being both alike provided with my improved dress. This flouring-surface is the surface upon the stones between which the finest crushing of the grain takes place, and which reducesthe previously-cracked grain into merchantable flour after the same has been bolted. These surfaces a are horizont-al, and made as smooth as possible by watergrinding, and extend from the periphery of the stones a proper distance inwardly toward the eye of the stones-say from w to x', as indicated in the figures ofthe drawings. From the inward termination of the plane surface (t the stones are cut away so as to form downwardlyinclined scouring and cracking surfaces b on the bed-stone, which extend to near the eye D of the stone, as shown. The upper stone has its surfaces b inclined upwardly. The stones are also cut away to form furrows c, which occupy positions on either side of the plane surfaces a throughout the faces of the stones, as indicated in the gures of the drawings. These furrows are cut from the periphery of the stones, and gradually incline from said periphery in a straight line to the eye D, as indicated in Figs. 4 and 7, and they are also, throughout their length, beveled transversely, so that the grain, when it passes into the` furrows from the eye of the stones, will, by the movement of the runner or the upper stone, be gradually carried forward to the cracking and flouring surfaces.

It will be seen by reference to Fi. 5 that when the runner and bed-stone are in position for grinding, as shown in said figure, a con cavity exists between the upper and lower stone, Which extends from the inner terminus, of the plane surface a, and gradually increases in volume to the eye l) of the stones, the concavity being in form of a hollow spheroid, so that the grain passing outwardly from the eye D will first be rubbed or scoured, and thus divestedot1 its bran; then, passing on, will be gradually cracked and granulated by the surfaces b until suiiciently reduced to pass in contact with and be ground to flour between the plane surfaces a, the fnrrows r serving the purpose of ventilation during such process directly from the eye 1).

It will also be seen that the heaviest pressure of the stones upon the crushed grain, and that which finally reduces it to flour, takes place at or near the periphery of the stones, where it is discharged, and hence. when the proper fineness has been attained, there will be an immediate escape or discharge of the flour, and regriuding and injurious overheating of' the ioury product cannot take place.

It will be seen that the surfaces a and b and the fnrrows c are all on straight lines tangential to the eye of the stones, and hence there will be no abrupt arrest or under-retardation of the cracked and ground product in its passage from the eye to the point of discharge of the stones; and that the inclination of the furrows from the eye to the periphery of the stones will not only prevent a too rapid outward delivery, but also that the furrow-surfaces, by reason of their formation, afford a gradually contracted and conductiu g space, in which said surfaces not only constantly keep hold of and comminute said product, but also conduct it to the ouring-surfaces c a.

What I claim as new and of my invention The millstonedress which consists of the peripheral finishing or iouring plane surfaces a a and inclined scouring and cracking bosomsnrfaces b b, in combination with the tangential straight furrows c c, shallow and broad at the skirt, running straight to the eye, with constantly' -increasing depth and decreasing width, substantially iu the manner described, and for the purpose set forth.

ELBERT S. (EUX.

Witnesses z ROBERT MCGULLY, l). LAWRENCE. 

